428 University of California Publications in Botany [Vol. 6 



with the result that small clusters of clavate cells held together at their 

 bases by a portion of the gelatinized wall are formed. 



14. Prior to abscission starch in large quantities is stored in the 

 abscission zone and later serves as a source of energy for growth follow- 

 ing separation. 



The writer wishes to acknowledge the obligation under which Pro- 

 fessor F. E. Lloyd has placed him for his many helpful suggestions 

 and interest in the investigation, and to express his appreciation to 

 Professor Thomas H. Goodspeed for helpful criticisms. 



LITERATURE CITED 



Atkins, W. R. G. 



1916. Some recent researches in plant physiology, London. 

 Bertbaxd, G., et Mallevre, A. 



1894. Sur la pectase et sur la fermentation pectique. Compt. Eend., vol. 



119, pp. 1012-14. 

 1895a. Nouvelles recherches sur la pectase et sur la fermentation pectique. 



Ibid., vol. 120, pp. 110-12. 

 1895?;. Sur la diffusion de la pectase dans le regne vegetal et sur la prepa- 

 ration de cette diastase. Ibid., vol. 121, pp. 726-28. 



BOURQUELOT, E. 



1899. Sur la pectase. Jour, pharm. et ehim., vol. 9, pp. 563-68. 

 BouRQUELOT, E., and Herissey, H. 



1898. De 1 'action des ferments soluble sur les produits pectiques de la racine 

 de gentione. Jour, pharm. et chem., vol. 8, pp. 145-50. 

 Brown, H. T., and Morris, G. H. 



1890. Researches on the germination of some of the Gramineae. Jour. 

 Chem. Soc, vol. 57, pp. 458-531. 

 Feemy, E. 



1840. Premiers essais sur la maturation des fruits. Recherches sur la 

 pectine et I'acide pectique. Jour, de p)hann., vol. 26, pp. 368-93. 

 Goodspeed, T. H., and Kendall, J. N. 



1916. On the partial sterility of Nicotiana hybrids made with N. sylvestris 



as a parent. III. An account of the mode of floral abscission in 

 the F, Species Hybrids. Univ. Calif. Publ. Bot., vol. 5, no. 10. 

 Hodgson, Robert W. 



1917. Some abnormal water relations in citrus trees of the arid Southwest 



and their possible significance. Univ. Calif. Publ. Agr. Sci., vol. 3, 

 no. 3. 

 Jones, L. R. 



1909. Pectinase, the cytolytic enzyme produced by BacUlm carotovorus and 

 certain other soft rot organisms. New York Agr. Exp. Sta., Tech. 

 Bull. no. 11. 

 Kendall, J. N. 



1917. Abscission in the Solanaceae, with special reference to Nicotiana, 

 Univ. Calif. Publ. Bot., vol. 5, no. 12. 

 Lloyd, Francis E. 



1916. Abscission in Mirabilis Jalapa. Bot. Gaz., vol. 61, no. 3. 



